Upholstered body and method of making same

ABSTRACT

AN UPHOLSTERED BODY, ESPECIALLY MATTRESS AND SEAT FOR AUTOMOBILES, AND METHOD OF MAKING THE SAME, ACCODING TO WHICH A CORE BODY OF COIL SPRINGS HAS A SEAMLESS COVER OF FOAMED MATERIAL, FOR INSTANCE, OF POLYESTER, OR POLYETHER, AROUND SAID CORE BODY.

United States Patent [191 Krier et al.

UPHOLSTERED BODY AND METHOD OF MAKING SAME Inventors: Phillip Krier,Stuttgart-Schonberg;

Lothar Fendler, Gerokstrasse Stuttgart, both of Germany Assignee:Mirabed AG, Zug, Switzerland Filed: May 4, 1972 Appl. No.: 250,328

Related US. Application Data.

Division of 881'. No. 753,391, Aug. 19, 1968, Pat. No. 3,660,876.

Foreign Application Priority Data [111 13,821,823 1 July2,'19f( 1Primary ExaminrCasmir A. Nunbcrg Attorney, Agent, or FirmJames S. Hight,Jr. et al.

57 ABSTRACT An upholstered body, especially mattress and seat forautomobiles, andmethod of making the same, according to which a corebody of coil springs has a seamless 1967 r. Aug Germany 1 G 50909 coverof foamed material, for instance, of polyester, or us. Cl. 5/351 5/269 Ipolyethe around Said corebody' Int. Cl A47c 23/04, A470 25/00 5 ChimssDrawing Figures Field of Search 5/267, 269, 351; 29/911 V 3 24 Zitil'i ii Z \v A W25 UPI-IOLSTERED BODY AND METHOD OF MAKING SAME This is adivision of application Ser. No. 753,391-K- rier et al, filed Aug. 19,1968, now U.S. Pat. No. 3,660,876, May 9, 1972.

The present invention relates to a mattress and method of making thesame, according to which a spring core is provided with a cover of foammaterial.

It is known to cover spring cores of mattresses with a two-sectionalhood of foam material, which hood is,- prior to covering the springcore, cut so as to form a development and is then glued or cemented.This method has the drawback that it is awkward and expensive.Furthermore, the gluing areas of the cover of foam material are easilydamaged.

It is, therefore, an object of the present invention to provide a methodof making a mattress which will assure a simple and complete cover of aspring core in a minimum of time. i

It is another object of this invention to provide a mattress and methodof making the same, according to which in one working step with theapplication of the cover on the spring core, the cover is additionallyprovided with a coating, for instance, of textile material.

It is also an object of this invention to provide a mattress which caneasily be reinforced at those areas which are particularly exposed todamage.

These and other objects and advantages of the invention will appear moreclearly from the following specification, in connection with theaccompanying drawings, in which:

FIG. 1 diagrammatically illustrates a cross section through a mattressaccording to the invention.

FIG. 2 shows a section through a further embodiment of a mattressaccording to the invention.

FIG. 3 is a top view of a cutout portion of a spring core of a mattressaccording to the invention.

FIG. 4 is a perspective view of the springs shown in FIG. 1.

FIG. 5 illustrates, similar to FIG. 3, a further embodiment of a springcore according to the invention The method according to the presentinvention according to which a spring core is covered with a cover offoam material, is characterized in that the prefabricated spring core ina foaming process is provided with a cover closed in itself ofpolyester, polyether, or a similar soft foam material. Due to the factthat the foam layer foams directly on the spring core and thus is shapedaccordingly, the covering or coating of the spring core can be effectedin a minimum of time. The spring core itself forms the inner form of thecover so that the latter will precisely fit. Furthermore, the coverprepared according to the invention is completely seamless so that evenwhen being relatively thin it will have a considerable strength.

The method according to the invention can easily be practiced when thespring core, prior to the foaming of the layer of foam material iscovered with textile material, synthetic material, or the like so that,at any rate, the layer of foam material will be prevented from passingbetween the springs or the windings thereof.

According to a further development of the invention, the prefabricatedspring core is,in a closed foaming mold, provided with a cover so thatthe outer shape of the cover will beprecisely predetermined.

According to a particularly advantageous step of the method according tothe present invention, the spring core is, prior to the foaming on ofthe layer of foam material, provided with a cover, for instance, oftextile fabric, since such textile fabric cover enters into an intimateconnection with the foam material in such a way that the air entrappedin the spring core can escape during the foaming process. This air corewill then, during the further foaming operation, produce a counterpressure against the foaming pressure. The thus formed air core istherefore during the manufacture of the mattress very advantageousduring the foaming operation.

In certain instances it is advantageous to provide the edges of themattress with a reinforcement. This reinforcement may, in conformitywith a further feature of the invention, be applied in the form of areinforcing fabric or the like which intimately combines with the softfoam. By means of this reinforcement, certain edges of the mattress maybe designed in a simple mannerv as form retaining edges. Textilefabric,wire fabric, fabric of synthetic material, wood or metal parts, areparticularly suitable for this reinforcement.

According to a further feature of the present inven tion, a coatinglayer for the spring core, for instance, a textile fabric, is insertedin the foaming mold, and the spring core is, in said mold,,covered withthe soft foam layer so that the coating layer firmly combines with thesoft foam layer. In this way it is possible in a single operation toprovide the spring core with the cover as well as with fabric material,for instance, cotton drill.

The cover layer is, due to its fixed connection with the soft foamcover, prevented from slipping. Due to this cover, also the reinforcingareas are covered by the inserted fabric. In order to make possible thatthe covering layer is precisely in conformity with the foaming mold,said covering layer is pressed against the inner wall of the mold by gasunder pressure. This gas filling is, advantageously, during theintroduction of soft foam, withdrawn to the extent to which the softfoamis introduced into the mold.

According to still another feature of the invention, the soft foam layeris thicker or thinner at the side of the spring core than it is at thetwo large surfaces of the spring core. The spring core may have a heightof 7.5 centimeters, and the soft foam layer at the top and bottomsidemay have a height of approximately 3 centi meters, while thesoftfoam layer at the sides may have a thickness of approximately 2centimeters. The thinner side parts of the soft foam layer have a higherweight per volume curing the foaming operation and thereby becomestiffer so that a laterial stiffening, and consequently an increase inthe form stability will be assured.

Referring now to the drawings in detail, a spring core 24 (FIG. 1) isprovidedwith a cover 25 which may be formed, for instance, by anenvelope of nettle cloth, jute, or the like. The thus formed spring core24' is placed in a foaming mold 26 which comprises two mold sections 27and .28. Between the inner surface of the foaming mold 26 and the outersurface of the cover 25, there is provided a gap 29 extending all theway around said spring core 24. The height of this gap corresponds tothe desired height of the layer of foam material. Thus, the spring core24 is floatingly arranged, and this floating mounting may be realized bypins or similar spacer means (not shown in the drawings). The materialto be foamed is then introduced into the closed mold composed of thesections 27 and 28 through one or more feeding passages 30 and is foameddirectly rial closed in itself forms the surface of the spring core.When the first foaming tests for mattresses with a spring core werecarried out, it was found that during the foaming, the textile fabricwhich surrounds the spring core enters an intimate and solid connectionwith the foam material so'that the air in the spring core will duringthe foaming operation be enclosed in an airtight manner with the resultthat an air core forms. This air core will during the foaming operationdevelop a counter pressure against the foam pressure during the foamingoperation to such an extent that an undesired compression of the springcore will be prevented. Consequently, form-true foam bodies properlycorresponding to the desired form are obtained in which the spring coreis firmly embedded FIG-2 shows a further embodiment of a mattress with apreferred size ratio between the spring core 24a and the cover 32 offoam material. At the top and bottom side, the layer 32 of foam materialhas a thickness which is only slightly less than .half the height of thespring core 240;. The lateral parts 33 of. the foam materiallayer 32 onthe other hand, are only slightly thicker than a fourth of the height ofthe spring core 24a. These lateral parts 33, however, have a greaterdensity and thus havean increased stiffness or rigidity. In the edges ofthe mattress, reinforcements 34 in the form of textile fabric or thelike are embedded in the layer32 of foam material so that the mattresswill have form retaining edges. The entire layer 32 of foam material isprovided with a cover or envelope 35, the inner surface of which is,over its entire surface, firmly connected with the layer 32 of foammaterial and, if desired, with the reinforcements 34.

As will be evident from FIGS. 3 and 4, the spring core of the mattressaccording to FIG. 2 comprises a plurality of springs l'which arearranged adjacent to each other in the longitudinal direction indicatedby the arrow 3 and in I transverse direction indicated by the arrow '4,and which whenlooking down on the spring core 24a have an annular orcorner shape. The springs are.in the transverse direction (arrow 4) ofthe spring core, arranged adjacent to eachother in rows 5 whereas inlongitudinal direction of the spring core (arrow 3) are arranged oneafter the other in rows 6,

- ways two fine wires 13 are arranged directly adjacent In view of therectangularcross-section of the springs in combination with theoutermost coils thereof respectively located in a plane parallel to theplane of the spring core, there will after the foaming of the cover 32be obtained a very high form stability ofthe spring core and, ifdesired, a firm connection between the cover 32 of the foam material andthe spring core 24a. The two end legs 17 of each spring are inclinedwith regard to the center of the spring core so that the cover 32 offoam material or the cover 25'cannot be damaged.

-As will be evident from FIG. 3, the springs I when seen from the tophave a substantially trapezoidal shape while each two legs 15, 16; 20,21 are forming a right angle with regard to each other and the other twooppositely located legs 18, 19 define with each other an angle ofslightly less than 20.

The springs 1 of the spring rows 6, 7 extending in the longitudinaldirection (arrow 3).of the spring core are arranged in the respectiverows-6, 7 in a position corresponding to each other. The springs 1 ofthe rows 6, 7 which extend in the longitudinal direction (arrow 3) andare adjacent'to each other in the transverse direction (arrow 4) areoffset with regard to each other by 90 in such a way that, for instance,the spring end legs 17 of said adjacent rows 6, 7 are offset to eachother by 90. The'springs of 'eachspring row extending in thelongitudinal direction (arrow 3) of the spring core are arranged in thesame position, but are offset with regard to the springs of the adjacentspring row by90". In'this way, the legs parallel to the plane of thespring core and respectively pertaining to two adjacent spring rows arelocated directly adjacent to each other while the legs 15, 16 which arearranged along a straight line one behind the otherare interconnected byfine wires 13 in such a way that according to FIGS. 3 and 4, al

to each other. This brings about that the legs 15, 16 of the adjacentspring rows can in response to a load act- 7. The individual springs areinterconnected by fine wires 8 10 extending in transversedirection.(arrow 4) and furthermore interconnected by fine wires 11 13extending in longitudinal direction (arrow 3).

As illustrated in FIG. 4, the outermost spring coils 14 of the springs 1are located in planes which are parallel to the plane of the springcore. These outermost coils are formed by three legs 15 16 arranged at aright angle with regard to each other. The next two legs 18,19 adjacentto the outermost spring coil 14 extend at an inclination with regard tothe plane of the spring core. The then adjacent legs 20, 21 of thespring 1 are again located in a plane parallel to the plane of the Ispring core. The inclination of the legs l8, 19 is so se- 1 lected thatthe distance of the legs 20, 21; 15, 16 which ing upon the spring movetoward each other and thereby can support each other.

The fact that the fine wires will cover the entire extension of thespring core enclose rectangulars of substantially identical sizes whichrespectively correspond to the plan view of two springs brings aboutthat there will be obtaineda very uniform" structure and thereby auniform spring effect and a uniform load distribution over the cover 32.The longitudinal central area of the spring core is reinforced by thefine wire 13 arranged in pairs adjacent to each other so that also inthe central area a sufficient force of the spring core will be assured.The asymmetry of the springs is balanced with regard to each other bythe offset arrangement of the individual springs. I I r The springs lare so arranged that in the longitudinal direction of the spring core(arrow 3) and in the transverse direction thereof (arrow 4) always twolegs 16, 20; 15,16; 21, 20, are located along a straight line and planeparallel to the plane of the spring ,core one behind the other. Thehelical'fine wires 8 l3 arewound around these just-mentioned legs of thespring 1. Within themarginal area 2 of the spring core, the outermostwindingsl4 are interconnectedby means of two fine wires 8, 9 ll, 12pointing in the same direction whereby an additional reinforcement ofthe marginal area 2 of the spring core will be assured.

Instead of reinforcing the marginal area 2 of the spring core by meansof two or more fine wires 8, 9;

11, 12, the marginal area 2 of the spring core may also be reinforced byone or more flat steel frames 22, as shown in FIG. 5. Such frame 22 isconnected to the marginal springs located in the marginal area and ispreferably embedded in the cover of foam material.

The ends 23 of the fine wires 8 13 are bent at a right angle and arewound around the legs of the corresponding springs 1, said legs formingthe marginal area 2 of the spring core.

The soft foam may be so foamed upon the cover 25 of the spring core thatit combines with the cover in such a way that this layer will have greatstrength, especially against wear. Between the spring core and the softfoam layer proper there is thus formed an intermediate layer which willassure a safe support on the spring core.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular arrangements shown in the drawings, butalso permits modifications, the invention being determined by the scopeof the appended claims.

It is furthermore to be understood, that the method according to theinvention is not limited to the making of mattresses, but also coversthe making of upholstered bodies, such as seats for automobiles, and thelike.

What we claim is:

1. An upholstered body which includes: a core body comprising aplurality of coiled wire springs, each coil of said springs when seen inaxial direction thereof having legs of an approximately quadrangular.contour while the outermost coils are at least partially located in aplane defining a major plane of the core body, said coils being arrangedin superimposed spaced planes and in rows extending in a first directionand also in rows extending in a second direction transverse to saidfirst direction, fine connection helical wire means having a diameterconsiderably less than the wire of said spring coils and interconnectingcoil legs extending in the same direction and located in substantiallythe same plane while pertaining to different coils, wrapping meansadjacent to the outer coils of said coiled springs and enclosing saidcoiled wire springs and a cover of soft foam material fully enclosingsaid wrapping means and said spring core.

2. An upholstered body according to claim 1, which includes a flatmetallic frame connected to the outermost coils of said coil springs andforming a part of said spring core.

3. An upholstered body according to claim 1, in which the outermostcoils which at least in part define a marginal surface of the core bodycomprise three legs angularly arranged with regard to each other.

4. An upholstered body according to claim 1, in which each of thesprings is offset by approximately with regard to at least one adjacentspring.

5. An upholstered body according to claim 1, in which the ends of saidsprings are inclined toward the center of the core body.

